2010-11 Deliverables

We mutually agree for Raul I. Cabrera to deliver the following
during the period of July 1, 2010 to June 30, 2011 using funds from
the Rio Grande Basin Initiative:

Evaluating rootzone stresses and the role of the root system on
rose crop productivity, fertilizer and water use efficiency. This
study will characterize the biomass and flower productivity
and quality, and physiological performance of rose plants
growing on their own roots versus grafted on a rootstock when
growing under challenging rootzone stresses, namely fertility
(nitrogen), salinity (including boron stress) and alkalinity
(varying pH conditions). The experiments will involve a split root
system approach that will only stress a portion of the root system,
effectively mimicking more closely the nature of rootzone stress
under standard commercial conditions.

Continue evaluating the water and nutrient use of three Texas
native street trees (Ulmus crassifolia, Celtislaevigata and Maclura pomifera) infested by the
parasitic xylem-tapping leafy mistletoe (Phoradendron
spp.). We will monitor water and nutrient use by
mistletoes in mature infected trees growing under a range of
landscape management conditions. This includes physiological
determinations of water relations and nutrient status (stomatal
conductance, water potential, chlorophyll, tissue nutrient
concentrations) in both the mistletoe and its hosts through a
second year. In addition, using container-grown cedar elms
(Ulmus crassifolia) manually infected with mistletoe, we
will measure, by mass-balance approaches, water and nitrogen
fertilizer use by the whole plants in comparison to non-infected
(control) plants, both under stressful and optimal management
conditions.

TWRI and the Texas A&M Natural Resources Institute are working together to foster and communicate research and educational outreach programs focused on water and natural resources science and management issues in Texas and beyond.